Be nice. Or else.
Not that I can think of, but Gmail was always the main reason we had to inline styles. There may be a few, very small, third-party edge cases, but once Gmail makes the update, embedded styles will have near universal support.
We'll see when it rolls out, but I suspect that the change is happening on their preprocessor/sanitizer that they use before emails even hit individual clients, so it should cover most of their email clients.
As Dylan mentioned, the worst case scenario for most people is now Outlook. The two good things about Outlook are that 1) all of their bugs are essentially known issues with known fixes and 2) Microsoft is actively looking to improve Outlook, so hopefully those problems will eventually be fixed.
It will potentially make a big difference in the short term, since designers will be able to stop inlining styles if they want to, which will be a big productivity win. It will help clean up the code and reduce style duplication and make the creation and maintenance of emails much, much better.
I don't think most people believed in the first place. Huge move from Gmail, not only opening up more traditional responsive design options, but will lead everyone away from using inline styles, too. Say hello to more compact, maintainable email code...
I literally wrote a post about this a while back: http://rodriguezcommaj.com/blog/whose-website-is-it-anyways/
+1 for first-person. Worry about being honest and showing off your best work, not about artificially inflating your sense of value.
We're all pretty big fans of DN, haha.
Another Litmus employee here (I see you Kevin), but just wanted to +1 to everything listed below. If you run into issues, you should definitely post questions about design/development in the Litmus Community: https://litmus.com/community/discussions
It's free to use and there are a ton of helpful and incredibly smart people in there.
I think most people in email design are in a similar boat. I've found that a lot of email marketing and design is an educational problem—making the stakeholders aware of the limitations and unique opportunities with email. It's an ongoing battle, but one worth fighting.
There actually is a section on animated GIFs.